//* static alien that fires guided missiles to ship

alien_launcher_images = new Images('launcher',1);

function AlienLauncher() {
  // contructor
  var that = new AlienCannon();
  that.images = alien_launcher_images;
  
  // update 
  that.update = function() {
    this.angle = Math.atan2(ship.y-this.y,ship.x-this.x);
    // fire every once in a while
    if (this.frame % 50 == 49) {
      var s = AlienMissiles(1,this.x,this.y);
      aliens.add(s);
    }
  }
  
  return that;
}

function AlienLaunchers(ACount) {
  // create array of aliens
  var that = new Array();
  for (var i=0; i<ACount; i++)
      that.push(new AlienLauncher());
  return that;  
}
